Dental pattern



y 0 I c. N. SKINNER 2,508,546

DENTAL PATTERN Filed March 50;"1948 2 Sheets-Sheet 1 INVENTOR 'C. N. SKINNER ATTORNEY Patented May 23, 1950 2,598,546 DENTAL PATTERN Clawson N. Skinner, Whittier, Calif. Application March so, 1948, Serial No. 17,831

This invention relates to partial dentures and more particularly to patterns for, and methods of fabricating partial dentures of the type disclosed in my prior Patent 2,279,351.

The prior patent teaches a detachable connection between a partial denture saddle and an anchor structure located at one end thereof. Specifically, the connection of the patent comf prises a sleeve member in the saddle that receives from the anchor struca bar member projecting ture. a

The prior patent teaches several ways of form-f ing the sleeve and bar members that constitute the connection, but in general, they are prefabricated in metal separate from the parts with which 1- Claim. (Cl. 22- 158) facilitate the production of partial dentures of the type in whichdetachable connection between the denture base and the anchor structure is effected by a bar, member on the anchor structure that extends into a sleeve member in the denture base.

Another object is to provide patterns of the sleeve and bar members that enable dentists to cast the bar member integral with the anchoring they are to be associated, the sleeve member being subsequently embedded in the denture saddle during the processing thereof,and the bar meniber being soldered to the anchoring device after the latter has been formed.

The prefabrication of the sleeve and barmembers insures that they will fit each other properly, but some dentists do not have the skill and facili-' ties for producing a strong solder connection between the bar member and the anchoring device. Furthermore, the anchoring device is often a metal casting fabricated to fit the natural teeth of the patient, by the well known lost wax process, and it would obviously be desirable to cast the bar member integral with the anchoring device." However, because of variable shrinkage of mold investments used in the lost wax process, it is impracticable for the average dentist to attempt to cast a bar member integral with the anchoring device and have that .bar member properly fit a prefabricated sleeve member that he could purchase.

This problem is solved in accordance with the;

present invention by the use of special standardized prefabricated patterns of the bar and sleeve members. The dentist attaches the special pattern of the bar member to the wax pattern of the anchoring device that he has prepared by.

conventional methods, embeds the composite pattern in the mold investment, and drives the wax and special pattern out by heat, leaving a mold cavity in which the anchoring device and integral bar member are cast. The special pattern of the sleeve member is embedded in a block of the same mold investment and is heated in the oven simultaneously with the first mold so that the shrinkage of the two molds is the same, and the bar and sleeve members that are cast in the mold fit properly. a v

An object of the invention is "tosimplify and transferred through the the natural teeth I5.

structure without spoiling the fit between the bar and sleeve members.

A full understanding bf. the manner. of accomplishment of the foregoing objects togetherwithw morespecific objects and features of the invention may be had from the detailed description.v

to follow with referenceto the drawing, in which: Fig. 1 is a plan view of a partial denture in accordance with the invention, shown anchored in position;

Fig. 2 is a side elevation with a part broken away, looking at the right side of Fig. 1; Fig. 3 is an enlarged plan view of the bar and sleeve connection employed in the structure of.

the denture Figs. 1 and 2,"a small portion of being shown in section;

Fig. 4 is a vertical section taken in the plane IV--IV of Fig. 3; v Fig. 5 is a view similar. to Fig. 3showing the members relieved to permit desired freedom of movement; I

Figs. 6 and 7 are plan and side elevation views respectively of a special pattern to be used in forming the bar member;

Figs. 8 and 9 are plan and side elevation views "respectively of a special pattern for use in forming the sleeve member; V

Fig. 10 is a view somewhat schematic in nature but showing a composite pattern embedded in the mold investment material in the process of forming a mold by the lost wax process; and

Fig. 11 is a plan view showing the component parts of the structure formed from the mold of V Fig. 10.

Referring to Fig. 1, there is illustrated a lower bilateral partial denture comprising apair or denture assemblies.l6, l6 which replace the nat-. v ural molars and are anchored in place by an.

anchor-structure ll which is secured to certain natural teeth [5. Each of the denture assemblies 16 comprises a base I8 of plastic or the like which is shaped to fit the tissues whereby masticatory forces are largely transferred directly to the tissues through the. base [8, instead of being anchor structure ll to of a sleeve member |9, and is secured thereto byv 7 The bar member 20 may be of rectangular cross section and tapered from a larger cross section at the end adjacent the anchoring structure H to a, smaller cross section at the outer end. The'sleeve member |9 may consist of a pair of sidewall members |9a lying alongside the bar 20 and connected at their outer ends byan 'end member I91) and at their'large end by :a cross member I90. To provide additional anchorage of the sleeve member IS in .thedenture base 18,

an extension 23 may .be soldered :or otherwise secured to the outer. end of'the sleeve member l9. An important purpose of the connection of V the denture assemblies Hi to the anchoring device I1 is to prevent the dentures from moving away from the tissues. To facilitate this purpose, upward movement of the outer endof the sleeve member H) with respect to thebar mem-. ber 20 is preventedby providing a step |9d (Fig.1

is preferably formed integrally with the anchoring. structure particularly when the latter is itself a casting formed by the lost wax process; .A pattern for production of the 'bar members:

20 integral with the cast .anchoring structure .1]

may be produced by the use of special .standardized, prefabricated patterns'of the bar and sleeve 'members, respectively, as illustrated in Figs. 6 to 9 inclusive. Thus the pattern "24 of Figs. '6 and '7 corresponds in shape j(as to its fes.-

sentialinterfittingportions), with the bar mem-.-'

ber-Zll of Figs. 3 and 4; The special pattern "25 fits the plastic bar pattern 24. These patterns 24, and :25 can be cast; pressed, or otherwise formed from some relatively hard and durable material that can be dissipated by heat. Suitable materials are polymers of methyl 'methacrylate;

and polymers of thevinyljresins. They are quite diiferent inthis respect from soft wax patterns; which wouldnot retain their shape during shipment and handling. The pattern 24 for the-bar member 20 may have a suitable stub 24a at its rear end for attachment to the wax pattern 21 (Fig. 10) which has been prepared by the dentist in the usual manner. Fig. 10 shows this wax pate tern 2'! with the special patterns 24 extending therefrom positioned in an investment mold '28 a suitable material. 'If' the casting is to be in gold, graphite is .a suitable material. Such aperture-'fillingpins are shown at 5.0 in'Fig. 10. When the mold 28 is heated in accordance with the usual practiceof the lost wax .proc ess,the wax of the pattern 2! "is volatilized anddrivenout 4 of the mold, leaving in its place a mold cavity of corresponding shape. The special patterns 24 are likewise dissipated by the heat, so that they leave their true outline in the mold 28. The 5 same is true of the special patterns 25. Further in accordance with the established procedure in the lost wax process, the mold 28 is then used to cast with molten metal the anchor structure (Fig. 11) having the bar members formed .-l0 integrally therewith. The-recuperating sleeve members. l9 are likewisecastat the same time.

Because of the fact that the special pattern i24i0f the bar member properly fitted the special pattern 25 of the sleeve member, and the cor- 1'5 responding elements'lB and 20 of Fig. 11 were .eastrin molds produced from the patterns 2 and 25 under identical conditions, the members l9 -:and'2|l=of '-1 ig.*1-1 will fit each other properly des pite shrinkage or expansion during the 20 processing, inasmuch as *any change in dimensions willbe the .same ,for'both elements.

While embedding thesleeve members IS in the denture base L8 .(duringtheprocessing of the'latter), the bar members 20 .are'inserted in .25 the sleeve members |9,..and the pins 2| are insertedas shown in Fig. 3 the threads 21a on'the V pin,2.| extending beyond the sleeve member 19, sogthat when .the @denture ,base .IB is formed around the .pin =corresponding threads are formed 30.;lnthebase l8. By reason of .this :threadedcon nection, pin 2| can be screwed out of the base vl3 at anytime itis desired to-disassemble the structureand withdraw the bar member 20 from the sleeve member 19. 5:

in Fig. .3, being cut oil flush with the surface of the denture base l8 ,after the latter has :been formed. ;The -;pins areshow n in their original length Fig. 1 1, from which it will be noted 40 jithe pins are extended beyond their threaded portions. ..-Forming the threads 2:|a'.( Fig.-3) in the gporifionpf "the ;pin 2| that is embedded in the plastic :base 18,, not only simplifies production by eliminatin the :operation of forming threads in sleeve memberv |.-9 .or bar member Zlljbut permits :the same patterns 22.4 and 25 to be used .in both "the right :andleft sides of rdentures.

,Asshown'in Fig. 25, afdBSlIGdilieB'dOm of move.- ment of "the bar member 20 with respect to the sleeve member 51.9 may be obtained by relieving the barhmembjer as indicated at the points 3 and 32 and/orrelievingthersleeve member .1 9 :at the points "33 and/or 134. This :relieving :may be performed by grinding -.or"-fili'ng.

Although for the :purpose of explaining the invention, a particular :embodimentthereof has been shown and described, obvious modifications will-occur to 'aper'son skilled in-the art, and I do 'not desire to be limited {to '-the :exact details shown and described.

Iclaimt'f j 7 An :article of manufacture for .use casting by the lost Wax process .a bar 'member integral 5 with a dental anchor structure and a cooperating sleeve member fittingsaid bar member, said articlecomprising: Iinterfitting patterns .of said. bar and sleeve members of a material relatively hard and durable as compared .to wax but dissipatable at temperatures employahle .in curing investments in the lost wax process.

cLA soN n. .SKINNER.

' v f rences en q lowine-vage), I V

The pin M e ri na y l n e tha as hown 5 REFERENCES CITED ggz The following references are of record in the 2:136:404 file of this patent: 2279351 UNITED STATES PATENTS 5 2,323,685 Number Name Date 1,262,973 Pack et a1 Apr. 16, 1918 2'461'416 1,357,503 Lucier NOV. 2, 1920 1,535,017 Cline Apr. 21, 1925' 10 1,595,338 Brazda et a1 Aug. 10, 1926 1,684,700 Hauptmeyer Sept. 18, 1928 2,056,415 Young Oct. 6, 1936 6 Name Date Jefferies Dec. 29, 1936 Wheeler Nov. 15, 1938 Skinner Apr. 14, 1942 Skinner July 6, 1943 Steinbock et a1. Nov. 14, 1944 Kohl May 21, 1946 Erdle et a1 Feb. 8, 1949 OTHER REFERENCES Metals and Alloys, October 1943, pages 784-788, inclusive, Precision Castings for Ordinance and Aircraft" by Wolf. 

